src/vnet/dpo/load_balance.c

   1 /*
   2  * Copyright (c) 2016 Cisco and/or its affiliates.
   3  * Licensed under the Apache License, Version 2.0 (the "License");
   4  * you may not use this file except in compliance with the License.
   5  * You may obtain a copy of the License at:
   6  *
   7  *     http://www.apache.org/licenses/LICENSE-2.0
   8  *
   9  * Unless required by applicable law or agreed to in writing, software
  10  * distributed under the License is distributed on an "AS IS" BASIS,
  11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12  * See the License for the specific language governing permissions and
  13  * limitations under the License.
  14  */
  15
  16 #include <vnet/dpo/load_balance.h>
  17 #include <vnet/dpo/load_balance_map.h>
  18 #include <vnet/dpo/drop_dpo.h>
  19 #include <vppinfra/math.h>              /* for fabs */
  20 #include <vnet/adj/adj.h>
  21 #include <vnet/adj/adj_internal.h>
  22 #include <vnet/fib/fib_urpf_list.h>
  23 #include <vnet/bier/bier_fwd.h>
  24 #include <vnet/fib/mpls_fib.h>
  25 #include <vnet/ip/ip4_inlines.h>
  26 #include <vnet/ip/ip6_inlines.h>
  27
  28 // clang-format off
  29
  30 /*
  31  * distribution error tolerance for load-balancing
  32  */
  33 const f64 multipath_next_hop_error_tolerance = 0.1;
  34
  35 static const char *load_balance_attr_names[] = LOAD_BALANCE_ATTR_NAMES;
  36
  37 /**
  38  * the logger
  39  */
  40 vlib_log_class_t load_balance_logger;
  41
  42 #define LB_DBG(_lb, _fmt, _args...)                                     \
  43 {                                                                       \
  44     vlib_log_debug(load_balance_logger,                                 \
  45                    "lb:[%U]:" _fmt,                                     \
  46                    format_load_balance, load_balance_get_index(_lb),    \
  47                    LOAD_BALANCE_FORMAT_NONE,                            \
  48                    ##_args);                                            \
  49 }
  50
  51 /**
  52  * Pool of all DPOs. It's not static so the DP can have fast access
  53  */
  54 load_balance_t *load_balance_pool;
  55
  56 /**
  57  * The one instance of load-balance main
  58  */
  59 load_balance_main_t load_balance_main = {
  60     .lbm_to_counters = {
  61         .name = "route-to",
  62         .stat_segment_name = "/net/route/to",
  63     },
  64     .lbm_via_counters = {
  65         .name = "route-via",
  66         .stat_segment_name = "/net/route/via",
  67     }
  68 };
  69
  70 f64
  71 load_balance_get_multipath_tolerance (void)
  72 {
  73     return (multipath_next_hop_error_tolerance);
  74 }
  75
  76 static inline index_t
  77 load_balance_get_index (const load_balance_t *lb)
  78 {
  79     return (lb - load_balance_pool);
  80 }
  81
  82 static inline dpo_id_t*
  83 load_balance_get_buckets (load_balance_t *lb)
  84 {
  85     if (LB_HAS_INLINE_BUCKETS(lb))
  86     {
  87         return (lb->lb_buckets_inline);
  88     }
  89     else
  90     {
  91         return (lb->lb_buckets);
  92     }
  93 }
  94
  95 static load_balance_t *
  96 load_balance_alloc_i (void)
  97 {
  98     load_balance_t *lb;
  99     u8 need_barrier_sync = 0;
 100     vlib_main_t *vm = vlib_get_main();
 101     ASSERT (vm->thread_index == 0);
 102
 103     pool_get_aligned_will_expand (load_balance_pool, need_barrier_sync,
 104                                   CLIB_CACHE_LINE_BYTES);
 105     if (need_barrier_sync)
 106         vlib_worker_thread_barrier_sync (vm);
 107
 108     pool_get_aligned(load_balance_pool, lb, CLIB_CACHE_LINE_BYTES);
 109     clib_memset(lb, 0, sizeof(*lb));
 110
 111     lb->lb_map = INDEX_INVALID;
 112     lb->lb_urpf = INDEX_INVALID;
 113
 114     if (need_barrier_sync == 0)
 115     {
 116         need_barrier_sync += vlib_validate_combined_counter_will_expand
 117             (&(load_balance_main.lbm_to_counters),
 118              load_balance_get_index(lb));
 119         need_barrier_sync += vlib_validate_combined_counter_will_expand
 120             (&(load_balance_main.lbm_via_counters),
 121              load_balance_get_index(lb));
 122         if (need_barrier_sync)
 123             vlib_worker_thread_barrier_sync (vm);
 124     }
 125
 126     vlib_validate_combined_counter(&(load_balance_main.lbm_to_counters),
 127                                    load_balance_get_index(lb));
 128     vlib_validate_combined_counter(&(load_balance_main.lbm_via_counters),
 129                                    load_balance_get_index(lb));
 130     vlib_zero_combined_counter(&(load_balance_main.lbm_to_counters),
 131                                load_balance_get_index(lb));
 132     vlib_zero_combined_counter(&(load_balance_main.lbm_via_counters),
 133                                load_balance_get_index(lb));
 134
 135     if (need_barrier_sync)
 136         vlib_worker_thread_barrier_release (vm);
 137
 138     return (lb);
 139 }
 140
 141 static u8*
 142 load_balance_format (index_t lbi,
 143                      load_balance_format_flags_t flags,
 144                      u32 indent,
 145                      u8 *s)
 146 {
 147     vlib_counter_t to, via;
 148     load_balance_t *lb;
 149     dpo_id_t *buckets;
 150     u32 i;
 151
 152     lb = load_balance_get(lbi);
 153     vlib_get_combined_counter(&(load_balance_main.lbm_to_counters), lbi, &to);
 154     vlib_get_combined_counter(&(load_balance_main.lbm_via_counters), lbi, &via);
 155     buckets = load_balance_get_buckets(lb);
 156
 157     s = format(s, "%U: ", format_dpo_type, DPO_LOAD_BALANCE);
 158     s = format(s, "[proto:%U ", format_dpo_proto, lb->lb_proto);
 159     s = format(s, "index:%d buckets:%d ", lbi, lb->lb_n_buckets);
 160     s = format(s, "uRPF:%d ", lb->lb_urpf);
 161     if (lb->lb_flags)
 162     {
 163         load_balance_attr_t attr;
 164
 165         s = format(s, "flags:[");
 166
 167         FOR_EACH_LOAD_BALANCE_ATTR(attr)
 168         {
 169             if (lb->lb_flags & (1 << attr))
 170             {
 171                 s = format (s, "%s", load_balance_attr_names[attr]);
 172             }
 173         }
 174         s = format(s, "] ");
 175     }
 176     s = format(s, "to:[%Ld:%Ld]", to.packets, to.bytes);
 177     if (0 != via.packets)
 178     {
 179         s = format(s, " via:[%Ld:%Ld]",
 180                    via.packets, via.bytes);
 181     }
 182     s = format(s, "]");
 183
 184     if (INDEX_INVALID != lb->lb_map)
 185     {
 186         s = format(s, "\n%U%U",
 187                    format_white_space, indent+4,
 188                    format_load_balance_map, lb->lb_map, indent+4);
 189     }
 190     for (i = 0; i < lb->lb_n_buckets; i++)
 191     {
 192         s = format(s, "\n%U[%d] %U",
 193                    format_white_space, indent+2,
 194                    i,
 195                    format_dpo_id,
 196                    &buckets[i], indent+6);
 197     }
 198     return (s);
 199 }
 200
 201 u8*
 202 format_load_balance (u8 * s, va_list * args)
 203 {
 204     index_t lbi = va_arg(*args, index_t);
 205     load_balance_format_flags_t flags = va_arg(*args, load_balance_format_flags_t);
 206
 207     return (load_balance_format(lbi, flags, 0, s));
 208 }
 209
 210 static u8*
 211 format_load_balance_dpo (u8 * s, va_list * args)
 212 {
 213     index_t lbi = va_arg(*args, index_t);
 214     u32 indent = va_arg(*args, u32);
 215
 216     return (load_balance_format(lbi, LOAD_BALANCE_FORMAT_DETAIL, indent, s));
 217 }
 218
 219 flow_hash_config_t
 220 load_balance_get_default_flow_hash (dpo_proto_t lb_proto)
 221 {
 222     switch (lb_proto)
 223     {
 224     case DPO_PROTO_IP4:
 225     case DPO_PROTO_IP6:
 226         return (IP_FLOW_HASH_DEFAULT);
 227
 228     case DPO_PROTO_MPLS:
 229         return (MPLS_FLOW_HASH_DEFAULT);
 230
 231     case DPO_PROTO_ETHERNET:
 232     case DPO_PROTO_BIER:
 233     case DPO_PROTO_NSH:
 234         break;
 235     }
 236
 237     return (0);
 238 }
 239
 240 static load_balance_t *
 241 load_balance_create_i (u32 num_buckets,
 242                        dpo_proto_t lb_proto,
 243                        flow_hash_config_t fhc)
 244 {
 245     load_balance_t *lb;
 246
 247     lb = load_balance_alloc_i();
 248     lb->lb_hash_config = fhc;
 249     lb->lb_n_buckets = num_buckets;
 250     lb->lb_n_buckets_minus_1 = num_buckets-1;
 251     lb->lb_proto = lb_proto;
 252
 253     if (!LB_HAS_INLINE_BUCKETS(lb))
 254     {
 255         vec_validate_aligned(lb->lb_buckets,
 256                              lb->lb_n_buckets - 1,
 257                              CLIB_CACHE_LINE_BYTES);
 258     }
 259
 260     LB_DBG(lb, "create");
 261
 262     return (lb);
 263 }
 264
 265 index_t
 266 load_balance_create (u32 n_buckets,
 267                      dpo_proto_t lb_proto,
 268                      flow_hash_config_t fhc)
 269 {
 270     return (load_balance_get_index(load_balance_create_i(n_buckets, lb_proto, fhc)));
 271 }
 272
 273 static inline void
 274 load_balance_set_bucket_i (load_balance_t *lb,
 275                            u32 bucket,
 276                            dpo_id_t *buckets,
 277                            const dpo_id_t *next)
 278 {
 279     dpo_stack(DPO_LOAD_BALANCE, lb->lb_proto, &buckets[bucket], next);
 280 }
 281
 282 void
 283 load_balance_set_bucket (index_t lbi,
 284                          u32 bucket,
 285                          const dpo_id_t *next)
 286 {
 287     load_balance_t *lb;
 288     dpo_id_t *buckets;
 289
 290     lb = load_balance_get(lbi);
 291     buckets = load_balance_get_buckets(lb);
 292
 293     ASSERT(bucket < lb->lb_n_buckets);
 294
 295     load_balance_set_bucket_i(lb, bucket, buckets, next);
 296 }
 297
 298 int
 299 load_balance_is_drop (const dpo_id_t *dpo)
 300 {
 301     load_balance_t *lb;
 302
 303     if (DPO_LOAD_BALANCE != dpo->dpoi_type)
 304         return (0);
 305
 306     lb = load_balance_get(dpo->dpoi_index);
 307
 308     if (1 == lb->lb_n_buckets)
 309     {
 310         return (dpo_is_drop(load_balance_get_bucket_i(lb, 0)));
 311     }
 312     return (0);
 313 }
 314
 315 u16
 316 load_balance_n_buckets (index_t lbi)
 317 {
 318     load_balance_t *lb;
 319
 320     lb = load_balance_get(lbi);
 321
 322     return (lb->lb_n_buckets);
 323 }
 324
 325 void
 326 load_balance_set_fib_entry_flags (index_t lbi,
 327                                   fib_entry_flag_t flags)
 328 {
 329     load_balance_t *lb;
 330
 331     lb = load_balance_get(lbi);
 332     lb->lb_fib_entry_flags = flags;
 333 }
 334
 335
 336 void
 337 load_balance_set_urpf (index_t lbi,
 338                        index_t urpf)
 339 {
 340     load_balance_t *lb;
 341     index_t old;
 342
 343     lb = load_balance_get(lbi);
 344
 345     /*
 346      * packets in flight we see this change. but it's atomic, so :P
 347      */
 348     old = lb->lb_urpf;
 349     lb->lb_urpf = urpf;
 350
 351     fib_urpf_list_unlock(old);
 352     fib_urpf_list_lock(urpf);
 353 }
 354
 355 index_t
 356 load_balance_get_urpf (index_t lbi)
 357 {
 358     load_balance_t *lb;
 359
 360     lb = load_balance_get(lbi);
 361
 362     return (lb->lb_urpf);
 363 }
 364
 365 const dpo_id_t *
 366 load_balance_get_bucket (index_t lbi,
 367                          u32 bucket)
 368 {
 369     load_balance_t *lb;
 370
 371     lb = load_balance_get(lbi);
 372
 373     return (load_balance_get_bucket_i(lb, bucket));
 374 }
 375
 376 static int
 377 next_hop_sort_by_weight (const load_balance_path_t * n1,
 378                          const load_balance_path_t * n2)
 379 {
 380     return ((int) n1->path_weight - (int) n2->path_weight);
 381 }
 382
 383 /* Given next hop vector is over-written with normalized one with sorted weights and
 384    with weights corresponding to the number of adjacencies for each next hop.
 385    Returns number of adjacencies in block. */
 386 u32
 387 ip_multipath_normalize_next_hops (const load_balance_path_t * raw_next_hops,
 388                                   load_balance_path_t ** normalized_next_hops,
 389                                   u32 *sum_weight_in,
 390                                   f64 multipath_next_hop_error_tolerance)
 391 {
 392     load_balance_path_t * nhs;
 393     uword n_nhs, n_adj, n_adj_left, i, sum_weight;
 394     f64 norm, error;
 395
 396     n_nhs = vec_len (raw_next_hops);
 397     ASSERT (n_nhs > 0);
 398     if (n_nhs == 0)
 399         return 0;
 400
 401     /* Allocate enough space for 2 copies; we'll use second copy to save original weights. */
 402     nhs = *normalized_next_hops;
 403     vec_validate (nhs, 2*n_nhs - 1);
 404
 405     /* Fast path: 1 next hop in block. */
 406     n_adj = n_nhs;
 407     if (n_nhs == 1)
 408     {
 409         nhs[0] = raw_next_hops[0];
 410         nhs[0].path_weight = 1;
 411         _vec_len (nhs) = 1;
 412         sum_weight = 1;
 413         goto done;
 414     }
 415
 416     else if (n_nhs == 2)
 417     {
 418         int cmp = next_hop_sort_by_weight (&raw_next_hops[0], &raw_next_hops[1]) < 0;
 419
 420         /* Fast sort. */
 421         nhs[0] = raw_next_hops[cmp];
 422         nhs[1] = raw_next_hops[cmp ^ 1];
 423
 424         /* Fast path: equal cost multipath with 2 next hops. */
 425         if (nhs[0].path_weight == nhs[1].path_weight)
 426         {
 427             nhs[0].path_weight = nhs[1].path_weight = 1;
 428             _vec_len (nhs) = 2;
 429             sum_weight = 2;
 430             goto done;
 431         }
 432     }
 433     else
 434     {
 435         clib_memcpy_fast (nhs, raw_next_hops, n_nhs * sizeof (raw_next_hops[0]));
 436         qsort (nhs, n_nhs, sizeof (nhs[0]), (void *) next_hop_sort_by_weight);
 437     }
 438
 439     /* Find total weight to normalize weights. */
 440     sum_weight = 0;
 441     for (i = 0; i < n_nhs; i++)
 442         sum_weight += nhs[i].path_weight;
 443
 444     /* In the unlikely case that all weights are given as 0, set them all to 1. */
 445     if (sum_weight == 0)
 446     {
 447         for (i = 0; i < n_nhs; i++)
 448             nhs[i].path_weight = 1;
 449         sum_weight = n_nhs;
 450     }
 451
 452     /* Save copies of all next hop weights to avoid being overwritten in loop below. */
 453     for (i = 0; i < n_nhs; i++)
 454         nhs[n_nhs + i].path_weight = nhs[i].path_weight;
 455
 456     /* Try larger and larger power of 2 sized adjacency blocks until we
 457        find one where traffic flows to within 1% of specified weights. */
 458     for (n_adj = max_pow2 (n_nhs); ; n_adj *= 2)
 459     {
 460         error = 0;
 461
 462         norm = n_adj / ((f64) sum_weight);
 463         n_adj_left = n_adj;
 464         for (i = 0; i < n_nhs; i++)
 465         {
 466             f64 nf = nhs[n_nhs + i].path_weight * norm; /* use saved weights */
 467             word n = flt_round_nearest (nf);
 468
 469             n = n > n_adj_left ? n_adj_left : n;
 470             n_adj_left -= n;
 471             error += fabs (nf - n);
 472             nhs[i].path_weight = n;
 473
 474             if (0 == nhs[i].path_weight)
 475             {
 476                 /*
 477                  * when the weight skew is high (norm is small) and n == nf.
 478                  * without this correction the path with a low weight would have
 479                  * no representation in the load-balanace - don't want that.
 480                  * If the weight skew is high so the load-balance has many buckets
 481                  * to allow it. pays ya money takes ya choice.
 482                  */
 483                 error = n_adj;
 484                 break;
 485             }
 486         }
 487
 488         nhs[0].path_weight += n_adj_left;
 489
 490         /* Less than 5% average error per adjacency with this size adjacency block? */
 491         if (error <= multipath_next_hop_error_tolerance*n_adj)
 492         {
 493             /* Truncate any next hops with zero weight. */
 494             _vec_len (nhs) = i;
 495             break;
 496         }
 497     }
 498
 499 done:
 500     /* Save vector for next call. */
 501     *normalized_next_hops = nhs;
 502     *sum_weight_in = sum_weight;
 503     return n_adj;
 504 }
 505
 506 static load_balance_path_t *
 507 load_balance_multipath_next_hop_fixup (const load_balance_path_t *nhs,
 508                                        dpo_proto_t drop_proto)
 509 {
 510     if (0 == vec_len(nhs))
 511     {
 512         load_balance_path_t *new_nhs = NULL, *nh;
 513
 514         /*
 515          * we need something for the load-balance. so use the drop
 516          */
 517         vec_add2(new_nhs, nh, 1);
 518
 519         nh->path_weight = 1;
 520         dpo_copy(&nh->path_dpo, drop_dpo_get(drop_proto));
 521
 522         return (new_nhs);
 523     }
 524
 525     return (NULL);
 526 }
 527
 528 /*
 529  * Fill in adjacencies in block based on corresponding
 530  * next hop adjacencies.
 531  */
 532 static void
 533 load_balance_fill_buckets_norm (load_balance_t *lb,
 534                                 load_balance_path_t *nhs,
 535                                 dpo_id_t *buckets,
 536                                 u32 n_buckets)
 537 {
 538     load_balance_path_t *nh;
 539     u16 ii, bucket;
 540
 541     bucket = 0;
 542
 543     /*
 544      * the next-hops have normalised weights. that means their sum is the number
 545      * of buckets we need to fill.
 546      */
 547     vec_foreach (nh, nhs)
 548     {
 549         for (ii = 0; ii < nh->path_weight; ii++)
 550         {
 551             ASSERT(bucket < n_buckets);
 552             load_balance_set_bucket_i(lb, bucket++, buckets, &nh->path_dpo);
 553         }
 554     }
 555 }
 556 static void
 557 load_balance_fill_buckets_sticky (load_balance_t *lb,
 558                                   load_balance_path_t *nhs,
 559                                   dpo_id_t *buckets,
 560                                   u32 n_buckets)
 561 {
 562     load_balance_path_t *nh, *fwding_paths;
 563     u16 ii, bucket, fpath;
 564
 565     fpath = bucket = 0;
 566     fwding_paths = NULL;
 567
 568     vec_foreach (nh, nhs)
 569     {
 570         if (!dpo_is_drop(&nh->path_dpo))
 571         {
 572             vec_add1(fwding_paths, *nh);
 573         }
 574     }
 575     if (vec_len(fwding_paths) == 0)
 576         fwding_paths = vec_dup(nhs);
 577
 578     /*
 579      * the next-hops have normalised weights. that means their sum is the number
 580      * of buckets we need to fill.
 581      */
 582     vec_foreach (nh, nhs)
 583     {
 584         for (ii = 0; ii < nh->path_weight; ii++)
 585         {
 586             ASSERT(bucket < n_buckets);
 587             if (!dpo_is_drop(&nh->path_dpo))
 588             {
 589                 load_balance_set_bucket_i(lb, bucket++, buckets, &nh->path_dpo);
 590             }
 591             else
 592             {
 593                 /* fill the bucks from the next up path */
 594                 load_balance_set_bucket_i(lb, bucket++, buckets, &fwding_paths[fpath].path_dpo);
 595                 fpath = (fpath + 1) % vec_len(fwding_paths);
 596             }
 597         }
 598     }
 599
 600     vec_free(fwding_paths);
 601 }
 602
 603 static void
 604 load_balance_fill_buckets (load_balance_t *lb,
 605                            load_balance_path_t *nhs,
 606                            dpo_id_t *buckets,
 607                            u32 n_buckets,
 608                            load_balance_flags_t flags)
 609 {
 610     if (flags & LOAD_BALANCE_FLAG_STICKY)
 611     {
 612         load_balance_fill_buckets_sticky(lb, nhs, buckets, n_buckets);
 613     }
 614     else
 615     {
 616         load_balance_fill_buckets_norm(lb, nhs, buckets, n_buckets);
 617     }
 618 }
 619
 620 static inline void
 621 load_balance_set_n_buckets (load_balance_t *lb,
 622                             u32 n_buckets)
 623 {
 624     lb->lb_n_buckets = n_buckets;
 625     lb->lb_n_buckets_minus_1 = n_buckets-1;
 626 }
 627
 628 void
 629 load_balance_multipath_update (const dpo_id_t *dpo,
 630                                const load_balance_path_t * raw_nhs,
 631                                load_balance_flags_t flags)
 632 {
 633     load_balance_path_t *nh, *nhs, *fixed_nhs;
 634     u32 sum_of_weights, n_buckets, ii;
 635     index_t lbmi, old_lbmi;
 636     load_balance_t *lb;
 637     dpo_id_t *tmp_dpo;
 638
 639     nhs = NULL;
 640
 641     ASSERT(DPO_LOAD_BALANCE == dpo->dpoi_type);
 642     lb = load_balance_get(dpo->dpoi_index);
 643     lb->lb_flags = flags;
 644     fixed_nhs = load_balance_multipath_next_hop_fixup(raw_nhs, lb->lb_proto);
 645     n_buckets =
 646         ip_multipath_normalize_next_hops((NULL == fixed_nhs ?
 647                                           raw_nhs :
 648                                           fixed_nhs),
 649                                          &nhs,
 650                                          &sum_of_weights,
 651                                          multipath_next_hop_error_tolerance);
 652
 653     ASSERT (n_buckets >= vec_len (raw_nhs));
 654
 655     /*
 656      * Save the old load-balance map used, and get a new one if required.
 657      */
 658     old_lbmi = lb->lb_map;
 659     if (flags & LOAD_BALANCE_FLAG_USES_MAP)
 660     {
 661         lbmi = load_balance_map_add_or_lock(n_buckets, sum_of_weights, nhs);
 662     }
 663     else
 664     {
 665         lbmi = INDEX_INVALID;
 666     }
 667
 668     if (0 == lb->lb_n_buckets)
 669     {
 670         /*
 671          * first time initialisation. no packets inflight, so we can write
 672          * at leisure.
 673          */
 674         load_balance_set_n_buckets(lb, n_buckets);
 675
 676         if (!LB_HAS_INLINE_BUCKETS(lb))
 677             vec_validate_aligned(lb->lb_buckets,
 678                                  lb->lb_n_buckets - 1,
 679                                  CLIB_CACHE_LINE_BYTES);
 680
 681         load_balance_fill_buckets(lb, nhs,
 682                                   load_balance_get_buckets(lb),
 683                                   n_buckets, flags);
 684         lb->lb_map = lbmi;
 685     }
 686     else
 687     {
 688         /*
 689          * This is a modification of an existing load-balance.
 690          * We need to ensure that packets inflight see a consistent state, that
 691          * is the number of reported buckets the LB has (read from
 692          * lb_n_buckets_minus_1) is not more than it actually has. So if the
 693          * number of buckets is increasing, we must update the bucket array first,
 694          * then the reported number. vice-versa if the number of buckets goes down.
 695          */
 696         if (n_buckets == lb->lb_n_buckets)
 697         {
 698             /*
 699              * no change in the number of buckets. we can simply fill what
 700              * is new over what is old.
 701              */
 702             load_balance_fill_buckets(lb, nhs,
 703                                       load_balance_get_buckets(lb),
 704                                       n_buckets, flags);
 705             lb->lb_map = lbmi;
 706         }
 707         else if (n_buckets > lb->lb_n_buckets)
 708         {
 709             /*
 710              * we have more buckets. the old load-balance map (if there is one)
 711              * will remain valid, i.e. mapping to indices within range, so we
 712              * update it last.
 713              */
 714             if (n_buckets > LB_NUM_INLINE_BUCKETS &&
 715                 lb->lb_n_buckets <= LB_NUM_INLINE_BUCKETS)
 716             {
 717                 /*
 718                  * the new increased number of buckets is crossing the threshold
 719                  * from the inline storage to out-line. Alloc the outline buckets
 720                  * first, then fixup the number. then reset the inlines.
 721                  */
 722                 ASSERT(NULL == lb->lb_buckets);
 723                 vec_validate_aligned(lb->lb_buckets,
 724                                      n_buckets - 1,
 725                                      CLIB_CACHE_LINE_BYTES);
 726
 727                 load_balance_fill_buckets(lb, nhs,
 728                                           lb->lb_buckets,
 729                                           n_buckets, flags);
 730                 CLIB_MEMORY_BARRIER();
 731                 load_balance_set_n_buckets(lb, n_buckets);
 732
 733                 CLIB_MEMORY_BARRIER();
 734
 735                 for (ii = 0; ii < LB_NUM_INLINE_BUCKETS; ii++)
 736                 {
 737                     dpo_reset(&lb->lb_buckets_inline[ii]);
 738                 }
 739             }
 740             else
 741             {
 742                 if (n_buckets <= LB_NUM_INLINE_BUCKETS)
 743                 {
 744                     /*
 745                      * we are not crossing the threshold and it's still inline buckets.
 746                      * we can write the new on the old..
 747                      */
 748                     load_balance_fill_buckets(lb, nhs,
 749                                               load_balance_get_buckets(lb),
 750                                               n_buckets, flags);
 751                     CLIB_MEMORY_BARRIER();
 752                     load_balance_set_n_buckets(lb, n_buckets);
 753                 }
 754                 else
 755                 {
 756                     /*
 757                      * we are not crossing the threshold. We need a new bucket array to
 758                      * hold the increased number of choices.
 759                      */
 760                     dpo_id_t *new_buckets, *old_buckets, *tmp_dpo;
 761
 762                     new_buckets = NULL;
 763                     old_buckets = load_balance_get_buckets(lb);
 764
 765                     vec_validate_aligned(new_buckets,
 766                                          n_buckets - 1,
 767                                          CLIB_CACHE_LINE_BYTES);
 768
 769                     load_balance_fill_buckets(lb, nhs, new_buckets,
 770                                               n_buckets, flags);
 771                     CLIB_MEMORY_BARRIER();
 772                     lb->lb_buckets = new_buckets;
 773                     CLIB_MEMORY_BARRIER();
 774                     load_balance_set_n_buckets(lb, n_buckets);
 775
 776                     vec_foreach(tmp_dpo, old_buckets)
 777                     {
 778                         dpo_reset(tmp_dpo);
 779                     }
 780                     vec_free(old_buckets);
 781                 }
 782             }
 783
 784             /*
 785              * buckets fixed. ready for the MAP update.
 786              */
 787             lb->lb_map = lbmi;
 788         }
 789         else
 790         {
 791             /*
 792              * bucket size shrinkage.
 793              * Any map we have will be based on the old
 794              * larger number of buckets, so will be translating to indices
 795              * out of range. So the new MAP must be installed first.
 796              */
 797             lb->lb_map = lbmi;
 798             CLIB_MEMORY_BARRIER();
 799
 800
 801             if (n_buckets <= LB_NUM_INLINE_BUCKETS &&
 802                 lb->lb_n_buckets > LB_NUM_INLINE_BUCKETS)
 803             {
 804                 /*
 805                  * the new decreased number of buckets is crossing the threshold
 806                  * from out-line storage to inline:
 807                  *   1 - Fill the inline buckets,
 808                  *   2 - fixup the number (and this point the inline buckets are
 809                  *       used).
 810                  *   3 - free the outline buckets
 811                  */
 812                 load_balance_fill_buckets(lb, nhs,
 813                                           lb->lb_buckets_inline,
 814                                           n_buckets, flags);
 815                 CLIB_MEMORY_BARRIER();
 816                 load_balance_set_n_buckets(lb, n_buckets);
 817                 CLIB_MEMORY_BARRIER();
 818
 819                 vec_foreach(tmp_dpo, lb->lb_buckets)
 820                 {
 821                     dpo_reset(tmp_dpo);
 822                 }
 823                 vec_free(lb->lb_buckets);
 824             }
 825             else
 826             {
 827                 /*
 828                  * not crossing the threshold.
 829                  *  1 - update the number to the smaller size
 830                  *  2 - write the new buckets
 831                  *  3 - reset those no longer used.
 832                  */
 833                 dpo_id_t *buckets;
 834                 u32 old_n_buckets;
 835
 836                 old_n_buckets = lb->lb_n_buckets;
 837                 buckets = load_balance_get_buckets(lb);
 838
 839                 load_balance_set_n_buckets(lb, n_buckets);
 840                 CLIB_MEMORY_BARRIER();
 841
 842                 load_balance_fill_buckets(lb, nhs, buckets,
 843                                           n_buckets, flags);
 844
 845                 for (ii = n_buckets; ii < old_n_buckets; ii++)
 846                 {
 847                     dpo_reset(&buckets[ii]);
 848                 }
 849             }
 850         }
 851     }
 852
 853     vec_foreach (nh, nhs)
 854     {
 855         dpo_reset(&nh->path_dpo);
 856     }
 857     vec_free(nhs);
 858     vec_free(fixed_nhs);
 859
 860     load_balance_map_unlock(old_lbmi);
 861 }
 862
 863 static void
 864 load_balance_lock (dpo_id_t *dpo)
 865 {
 866     load_balance_t *lb;
 867
 868     lb = load_balance_get(dpo->dpoi_index);
 869
 870     lb->lb_locks++;
 871 }
 872
 873 static void
 874 load_balance_destroy (load_balance_t *lb)
 875 {
 876     dpo_id_t *buckets;
 877     int i;
 878
 879     buckets = load_balance_get_buckets(lb);
 880
 881     for (i = 0; i < lb->lb_n_buckets; i++)
 882     {
 883         dpo_reset(&buckets[i]);
 884     }
 885
 886     LB_DBG(lb, "destroy");
 887     if (!LB_HAS_INLINE_BUCKETS(lb))
 888     {
 889         vec_free(lb->lb_buckets);
 890     }
 891
 892     fib_urpf_list_unlock(lb->lb_urpf);
 893     load_balance_map_unlock(lb->lb_map);
 894
 895     pool_put(load_balance_pool, lb);
 896 }
 897
 898 static void
 899 load_balance_unlock (dpo_id_t *dpo)
 900 {
 901     load_balance_t *lb;
 902
 903     lb = load_balance_get(dpo->dpoi_index);
 904
 905     lb->lb_locks--;
 906
 907     if (0 == lb->lb_locks)
 908     {
 909         load_balance_destroy(lb);
 910     }
 911 }
 912
 913 static void
 914 load_balance_mem_show (void)
 915 {
 916     fib_show_memory_usage("load-balance",
 917                           pool_elts(load_balance_pool),
 918                           pool_len(load_balance_pool),
 919                           sizeof(load_balance_t));
 920     load_balance_map_show_mem();
 921 }
 922
 923 static u16
 924 load_balance_dpo_get_mtu (const dpo_id_t *dpo)
 925 {
 926     const dpo_id_t *buckets;
 927     load_balance_t *lb;
 928     u16 i, mtu = 0xffff;
 929
 930     lb = load_balance_get(dpo->dpoi_index);
 931     buckets = load_balance_get_buckets(lb);
 932
 933     for (i = 0; i < lb->lb_n_buckets; i++)
 934     {
 935         mtu = clib_min (mtu, dpo_get_mtu (&buckets[i]));
 936     }
 937
 938     return (mtu);
 939 }
 940
 941 const static dpo_vft_t lb_vft = {
 942     .dv_lock = load_balance_lock,
 943     .dv_unlock = load_balance_unlock,
 944     .dv_format = format_load_balance_dpo,
 945     .dv_mem_show = load_balance_mem_show,
 946     .dv_get_mtu = load_balance_dpo_get_mtu,
 947 };
 948
 949 /**
 950  * @brief The per-protocol VLIB graph nodes that are assigned to a load-balance
 951  *        object.
 952  *
 953  * this means that these graph nodes are ones from which a load-balance is the
 954  * parent object in the DPO-graph.
 955  *
 956  * We do not list all the load-balance nodes, such as the *-lookup. instead
 957  * we are relying on the correct use of the .sibling_of field when setting
 958  * up these sibling nodes.
 959  */
 960 const static char* const load_balance_ip4_nodes[] =
 961 {
 962     "ip4-load-balance",
 963     NULL,
 964 };
 965 const static char* const load_balance_ip6_nodes[] =
 966 {
 967     "ip6-load-balance",
 968     NULL,
 969 };
 970 const static char* const load_balance_mpls_nodes[] =
 971 {
 972     "mpls-load-balance",
 973     NULL,
 974 };
 975 const static char* const load_balance_l2_nodes[] =
 976 {
 977     "l2-load-balance",
 978     NULL,
 979 };
 980 const static char* const load_balance_nsh_nodes[] =
 981 {
 982     "nsh-load-balance",
 983     NULL
 984 };
 985 const static char* const load_balance_bier_nodes[] =
 986 {
 987     "bier-load-balance",
 988     NULL,
 989 };
 990 const static char* const * const load_balance_nodes[DPO_PROTO_NUM] =
 991 {
 992     [DPO_PROTO_IP4]  = load_balance_ip4_nodes,
 993     [DPO_PROTO_IP6]  = load_balance_ip6_nodes,
 994     [DPO_PROTO_MPLS] = load_balance_mpls_nodes,
 995     [DPO_PROTO_ETHERNET] = load_balance_l2_nodes,
 996     [DPO_PROTO_NSH] = load_balance_nsh_nodes,
 997     [DPO_PROTO_BIER] = load_balance_bier_nodes,
 998 };
 999
1000 void
1001 load_balance_module_init (void)
1002 {
1003     index_t lbi;
1004
1005     dpo_register(DPO_LOAD_BALANCE, &lb_vft, load_balance_nodes);
1006
1007     /*
1008      * Special LB with index zero. we need to define this since the v4 mtrie
1009      * assumes an index of 0 implies the ply is empty. therefore all 'real'
1010      * adjs need a non-zero index.
1011      * This should never be used, but just in case, stack it on a drop.
1012      */
1013     lbi = load_balance_create(1, DPO_PROTO_IP4, 0);
1014     load_balance_set_bucket(lbi, 0, drop_dpo_get(DPO_PROTO_IP4));
1015
1016     load_balance_logger =
1017         vlib_log_register_class("dpo", "load-balance");
1018
1019     load_balance_map_module_init();
1020 }
1021
1022 static clib_error_t *
1023 load_balance_show (vlib_main_t * vm,
1024                    unformat_input_t * input,
1025                    vlib_cli_command_t * cmd)
1026 {
1027     index_t lbi = INDEX_INVALID;
1028
1029     while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
1030     {
1031         if (unformat (input, "%d", &lbi))
1032             ;
1033         else
1034             break;
1035     }
1036
1037     if (INDEX_INVALID != lbi)
1038     {
1039         if (pool_is_free_index(load_balance_pool, lbi))
1040         {
1041             vlib_cli_output (vm, "no such load-balance:%d", lbi);
1042         }
1043         else
1044         {
1045             vlib_cli_output (vm, "%U", format_load_balance, lbi,
1046                          LOAD_BALANCE_FORMAT_DETAIL);
1047         }
1048     }
1049     else
1050     {
1051         load_balance_t *lb;
1052
1053         pool_foreach (lb, load_balance_pool)
1054          {
1055             vlib_cli_output (vm, "%U", format_load_balance,
1056                              load_balance_get_index(lb),
1057                              LOAD_BALANCE_FORMAT_NONE);
1058         }
1059     }
1060
1061     return 0;
1062 }
1063
1064 VLIB_CLI_COMMAND (load_balance_show_command, static) = {
1065     .path = "show load-balance",
1066     .short_help = "show load-balance [<index>]",
1067     .function = load_balance_show,
1068 };
1069
1070
1071 always_inline u32
1072 ip_flow_hash (void *data)
1073 {
1074   ip4_header_t *iph = (ip4_header_t *) data;
1075
1076   if ((iph->ip_version_and_header_length & 0xF0) == 0x40)
1077     return ip4_compute_flow_hash (iph, IP_FLOW_HASH_DEFAULT);
1078   else
1079     return ip6_compute_flow_hash ((ip6_header_t *) iph, IP_FLOW_HASH_DEFAULT);
1080 }
1081
1082 always_inline u64
1083 mac_to_u64 (u8 * m)
1084 {
1085   return (*((u64 *) m) & 0xffffffffffff);
1086 }
1087
1088 always_inline u32
1089 l2_flow_hash (vlib_buffer_t * b0)
1090 {
1091   ethernet_header_t *eh;
1092   u64 a, b, c;
1093   uword is_ip, eh_size;
1094   u16 eh_type;
1095
1096   eh = vlib_buffer_get_current (b0);
1097   eh_type = clib_net_to_host_u16 (eh->type);
1098   eh_size = ethernet_buffer_header_size (b0);
1099
1100   is_ip = (eh_type == ETHERNET_TYPE_IP4 || eh_type == ETHERNET_TYPE_IP6);
1101
1102   /* since we have 2 cache lines, use them */
1103   if (is_ip)
1104     a = ip_flow_hash ((u8 *) vlib_buffer_get_current (b0) + eh_size);
1105   else
1106     a = eh->type;
1107
1108   b = mac_to_u64 ((u8 *) eh->dst_address);
1109   c = mac_to_u64 ((u8 *) eh->src_address);
1110   hash_mix64 (a, b, c);
1111
1112   return (u32) c;
1113 }
1114
1115 typedef struct load_balance_trace_t_
1116 {
1117     index_t lb_index;
1118 } load_balance_trace_t;
1119
1120 always_inline uword
1121 load_balance_inline (vlib_main_t * vm,
1122                      vlib_node_runtime_t * node,
1123                      vlib_frame_t * frame,
1124                      int is_l2)
1125 {
1126   u32 n_left_from, next_index, *from, *to_next;
1127
1128   from = vlib_frame_vector_args (frame);
1129   n_left_from = frame->n_vectors;
1130
1131   next_index = node->cached_next_index;
1132
1133   while (n_left_from > 0)
1134     {
1135       u32 n_left_to_next;
1136
1137       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
1138
1139       while (n_left_from > 0 && n_left_to_next > 0)
1140         {
1141           vlib_buffer_t *b0;
1142           u32 bi0, lbi0, next0;
1143           const dpo_id_t *dpo0;
1144           const load_balance_t *lb0;
1145
1146           bi0 = from[0];
1147           to_next[0] = bi0;
1148           from += 1;
1149           to_next += 1;
1150           n_left_from -= 1;
1151           n_left_to_next -= 1;
1152
1153           b0 = vlib_get_buffer (vm, bi0);
1154
1155           /* lookup dst + src mac */
1156           lbi0 =  vnet_buffer (b0)->ip.adj_index[VLIB_TX];
1157           lb0 = load_balance_get(lbi0);
1158
1159           if (is_l2)
1160           {
1161               vnet_buffer(b0)->ip.flow_hash = l2_flow_hash(b0);
1162           }
1163           else
1164           {
1165               /* it's BIER */
1166               const bier_hdr_t *bh0 = vlib_buffer_get_current(b0);
1167               vnet_buffer(b0)->ip.flow_hash = bier_compute_flow_hash(bh0);
1168           }
1169
1170           dpo0 = load_balance_get_bucket_i(lb0,
1171                                            vnet_buffer(b0)->ip.flow_hash &
1172                                            (lb0->lb_n_buckets_minus_1));
1173
1174           next0 = dpo0->dpoi_next_node;
1175           vnet_buffer (b0)->ip.adj_index[VLIB_TX] = dpo0->dpoi_index;
1176
1177           if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
1178             {
1179               load_balance_trace_t *tr = vlib_add_trace (vm, node, b0,
1180                                                          sizeof (*tr));
1181               tr->lb_index = lbi0;
1182             }
1183           vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
1184                                            n_left_to_next, bi0, next0);
1185         }
1186
1187       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
1188     }
1189
1190   return frame->n_vectors;
1191 }
1192
1193 static uword
1194 l2_load_balance (vlib_main_t * vm,
1195                  vlib_node_runtime_t * node,
1196                  vlib_frame_t * frame)
1197 {
1198     return (load_balance_inline(vm, node, frame, 1));
1199 }
1200
1201 static u8 *
1202 format_l2_load_balance_trace (u8 * s, va_list * args)
1203 {
1204   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
1205   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
1206   load_balance_trace_t *t = va_arg (*args, load_balance_trace_t *);
1207
1208   s = format (s, "L2-load-balance: index %d", t->lb_index);
1209   return s;
1210 }
1211
1212 /**
1213  * @brief
1214  */
1215 VLIB_REGISTER_NODE (l2_load_balance_node) = {
1216   .function = l2_load_balance,
1217   .name = "l2-load-balance",
1218   .vector_size = sizeof (u32),
1219
1220   .format_trace = format_l2_load_balance_trace,
1221   .n_next_nodes = 1,
1222   .next_nodes = {
1223       [0] = "error-drop",
1224   },
1225 };
1226
1227 static uword
1228 nsh_load_balance (vlib_main_t * vm,
1229                  vlib_node_runtime_t * node,
1230                  vlib_frame_t * frame)
1231 {
1232   u32 n_left_from, next_index, *from, *to_next;
1233
1234   from = vlib_frame_vector_args (frame);
1235   n_left_from = frame->n_vectors;
1236
1237   next_index = node->cached_next_index;
1238
1239   while (n_left_from > 0)
1240     {
1241       u32 n_left_to_next;
1242
1243       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
1244
1245       while (n_left_from > 0 && n_left_to_next > 0)
1246         {
1247           vlib_buffer_t *b0;
1248           u32 bi0, lbi0, next0, *nsh0;
1249           const dpo_id_t *dpo0;
1250           const load_balance_t *lb0;
1251
1252           bi0 = from[0];
1253           to_next[0] = bi0;
1254           from += 1;
1255           to_next += 1;
1256           n_left_from -= 1;
1257           n_left_to_next -= 1;
1258
1259           b0 = vlib_get_buffer (vm, bi0);
1260
1261           lbi0 =  vnet_buffer (b0)->ip.adj_index[VLIB_TX];
1262           lb0 = load_balance_get(lbi0);
1263
1264           /* SPI + SI are the second word of the NSH header */
1265           nsh0 = vlib_buffer_get_current (b0);
1266           vnet_buffer(b0)->ip.flow_hash = nsh0[1] % lb0->lb_n_buckets;
1267
1268           dpo0 = load_balance_get_bucket_i(lb0,
1269                                            vnet_buffer(b0)->ip.flow_hash &
1270                                            (lb0->lb_n_buckets_minus_1));
1271
1272           next0 = dpo0->dpoi_next_node;
1273           vnet_buffer (b0)->ip.adj_index[VLIB_TX] = dpo0->dpoi_index;
1274
1275           if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
1276             {
1277               load_balance_trace_t *tr = vlib_add_trace (vm, node, b0,
1278                                                          sizeof (*tr));
1279               tr->lb_index = lbi0;
1280             }
1281           vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
1282                                            n_left_to_next, bi0, next0);
1283         }
1284
1285       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
1286     }
1287
1288   return frame->n_vectors;
1289 }
1290
1291 static u8 *
1292 format_nsh_load_balance_trace (u8 * s, va_list * args)
1293 {
1294   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
1295   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
1296   load_balance_trace_t *t = va_arg (*args, load_balance_trace_t *);
1297
1298   s = format (s, "NSH-load-balance: index %d", t->lb_index);
1299   return s;
1300 }
1301
1302 /**
1303  * @brief
1304  */
1305 VLIB_REGISTER_NODE (nsh_load_balance_node) = {
1306   .function = nsh_load_balance,
1307   .name = "nsh-load-balance",
1308   .vector_size = sizeof (u32),
1309
1310   .format_trace = format_nsh_load_balance_trace,
1311   .n_next_nodes = 1,
1312   .next_nodes = {
1313       [0] = "error-drop",
1314   },
1315 };
1316
1317 static u8 *
1318 format_bier_load_balance_trace (u8 * s, va_list * args)
1319 {
1320   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
1321   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
1322   load_balance_trace_t *t = va_arg (*args, load_balance_trace_t *);
1323
1324   s = format (s, "BIER-load-balance: index %d", t->lb_index);
1325   return s;
1326 }
1327
1328 static uword
1329 bier_load_balance (vlib_main_t * vm,
1330                    vlib_node_runtime_t * node,
1331                    vlib_frame_t * frame)
1332 {
1333     return (load_balance_inline(vm, node, frame, 0));
1334 }
1335
1336 /**
1337  * @brief
1338  */
1339 VLIB_REGISTER_NODE (bier_load_balance_node) = {
1340   .function = bier_load_balance,
1341   .name = "bier-load-balance",
1342   .vector_size = sizeof (u32),
1343
1344   .format_trace = format_bier_load_balance_trace,
1345   .sibling_of = "mpls-load-balance",
1346 };
1347
1348 // clang-format on